Method of preparing alkyl phenol-formaldehyde condensates

ABSTRACT

Additives of improving the low temperature flow properties and oxidative stability of hydrocarbon oils are disclosed, which comprise the alkylation of a phenol in the presence of a polar aprotic cosolvent to produce an essentially linear alkylated phenol which is condensed with an aldehyde to produce the low temperature flow improver wherein: 
     (a) the polymer composition has a number average molecular weight of at least about 3,000 and a molecular weight distribution of at least about 1.5; 
     (b) in the alkylated phenol reactant the alkyl groups (i) are essentially linear; (ii) have between 6 and 50 carbon atoms; and (iii) have an average number of carbon atoms between about 12 and 26; and 
     (c) not more than about 10 mole percent of the alkyl groups on the alkylated phenol have less than 12 carbon atoms and not more than about 10 mole percent of the alkyl groups on the alkylated phenol have more than 26 carbon atoms. The additives may also be produced in a branched backbone form in which monomer reactants are copolymerized with certain tri- or tetrafunctional comonomers. Blends of these additives with various hydrocarbon oils, and particularly various middle distillates and lubricating oil compositions, whose low temperature flow properties and oxidative stability are significantly improved thereby, are also disclosed.

FIELD OF THE INVENTION

The present invention relates to additives for improving the lowtemperature flow properties of hydrocarbon oils. More particularly, thepresent invention relates to an improved process for preparing additivesfor improving the flow properties of fuel oil and lubricating oilcompositions.

BACKGROUND OF THE INVENTION

A large variety of additives for improving various properties inhydrocarbon oil compositions are well known, and in fact a large numberof these compositions are being used on a commercial level. The variousadditives are used for a variety of purposes, many of which relate toimproving the low temperature (i.e., less than about 30° F.) flowproperties of various types of hydrocarbon oils, including bothlubricating oil fractions and other oil fractions including heatingoils, diesel oils, middle distillates, and the like. In particular,these flow improvers generally modify the wax crystals in bothlubricating oils and other hydrocarbon fractions and crudes so as toimpart low temperature handling, pumpability, and/or vehicle operabilitythereto. These parameters are generally measured by a variety of tests,including pour point, cloud point, mini-rotary viscometry (MRV) andothers. Other such additives are used primarily for imparting otherproperties to these hydrocarbon fractions, including lubricating oilfractions, such as anti-oxidant properties and the like.

Cloud point (ASTM D 2500) is the temperature at which wax crystals firstappear as a haze in a hydrocarbon oil upon cooling. Such wax crystalstypically have the highest molecular weight of the waxes in thehydrocarbon oil and therefore the lowest solubility. The cloud point ofa hydrocarbon oil reflects the temperature at which problems infiltering the oil are encountered. However, the cloud point of alubricating oil (as opposed to a fuel oil) is of less significance thanis its pour point because the filters typically encountered by alubricating oil (e.g., combustion engine oil filters) have a relativelylarge pore size, and filter plugging is therefore less of a problem inthese environments.

Pour point is the lowest temperature at which a hydrocarbon oil willpour or flow when chilled, without disturbance, under specifiedconditions. Pour point problems arise through the formation of solid orsemisolid waxy particles in a hydrocarbon oil composition under chilledconditions. Thus, as the temperature of the oil is decreased, thedistribution of such oil by pumping or siphoning is rendered difficultor impossible when the temperature of this oil is around or below thepour point of the oil. Consequently, when the flow of oil cannot bemaintained, equipment can fail to operate.

It has therefore been necessary to develop various additives for thepurpose of influencing the cold temperature flow properties ofhydrocarbon oils.

The general term "lubricating oil flow improver" (LOFI) covers all thoseadditives which modify the size, number, and growth of wax crystals inlube oils in such a way as to impart improved low temperature handling,pumpability, and/or vehicle operability as measured by such tests aspour point, cloud point, and mini rotary viscometry (MRV). The majorityof lubricating oil flow improvers are polymers or contain polymers.These polymers are generally of two types, either backbone or sidechain.

The backbone variety, such as the ethylene-vinyl acetates (EVA), havevarious lengths of methylene segments randomly distributed in thebackbone of the polymer, which associate or cocrystallize with the waxcrystals inhibiting further crystal growth due to branches andnon-crystallizable segments in the polymer.

The sidechain-type polymers, which are the predominant variety used asLOFIs, have methylene segments as the side chains, preferably asstraight side chains. These polymers work similarly to the backbone typeexcept the side chains have been found more effective in treatingisoparaffins as well as n-paraffins found in lube oils. Morespecifically, LOFIs are typically derived from unsaturated carboxylicacids or anhydrides which are esterified to provide pendent ester groupsderived from a mixture of alcohols. Most current commercial additives ofthis type thus require the use of relatively expensive alcohols fortheir production. Representative examples of this type of side chainLOFI include dialkyl fumarate/vinyl acetate copolymers and esterifiedstyrene/maleic anhydride copolymers.

One additive composition which has been disclosed as a pour depressantfor fuels and crude oils is set forth in British Patent No. 1,173,975.The additive disclosed in this patent is a phenol-aldehyde (preferablyformaldehyde) polymer in which the phenol has an R-- or RCO--substituent in which R is hydrocarbyl or substituted hydrocarbyl. R isfurther said to contain from 18 to 30 carbon atoms, and is preferably astraight-chain alkyl group. The specific examples in this patent whichuse olefins to provide these R groups include various internal olefins,and there is no specific disclosure regarding the advantages of usingterminal olefins therein. Another patent, British Patent No. 1,167,427,discloses the use of esters of such phenolaldehyde polymers for pourreduction of fuel oils. In both of these British patents, the oils to betreated are said to have a maximum viscosity of about 1500 cSt at 100°F., and neither recognizes the significance of utilizing specificalpha-olefins and mixtures thereof to produce these condensationproducts or the advantages of imparting essential linearity to theolefin-derived side chains.

Another additive composition which has been disclosed for use as a pourpoint depressant, so as to modify the surface of the wax containedwithin lubricating and fuel oil compositions by absorption orco-crystallization so as to reduce the fluid occlusion by thesecrystals, is a phenolic compound disclosed in U.S. Pat. No. 3,336,226.The compound shown in this patent is an alkyl phenol trimer havingmethylenic bridges which is monosubstituted by alkyl groups of between14 and 25 carbon atoms. This patent specifically discloses having numberaverage molecular weights far lower than 3,000, in fact, lower than1,500, and furthermore broadly discloses the use of olefins foralkylation of the phenol compositions prior to condensation withformaldehyde. The olefins disclosed in this patent are either terminalor internal olefins, and a trimer is prepared by conducting thecondensation reaction in the presence of a metal hydroxide. Moreover,alkylation process conditions are not controlled to minimizerearrangement of even the terminal olefins.

Another lubricating oil composition is disclosed in U.S. Pat. No.3,248,361. In this case cylinder lubricants are modified in order toreduce combustion chamber deposits by using an additive product of anolefin oxide with either a sulfur modified condensation product of asubstituted monohydric phenol that includes a hydrocarbon substituentcontaining from 4 to 18 carbon atoms and an aliphatic aldehyde, or apartial salt of that sulfurmodified condensation product and an alkalimetal, ammonia, or a Group II metal. This patent does not disclose acondensation product of an alkylated phenol and an aldehyde. U.S. Pat.No. 3,951,830 discloses lubricant additives particularly used asoxidation inhibitors comprising sulfur and methylene bridged polyphenolcompositions. These are prepared by reacting phenol with formaldehydefollowed by sulfurization or by sulfurizing phenols prior to reactionwith formaldehyde. This patent also discloses phenols which aresubstituted with aliphatic or cycloaliphatic radicals of a wide rangeand variety, and it also discloses the use of poly-substitutedmaterials, such as dialkyl and trialkyl phenols therein. All of theexamples in this patent employ tetrapropene, polyisobutene, and othersuch substituted phenol compositions therein, and not essentially linearalkylated phenols of a specified length.

U.S. Pat. No. 4,446,039 discloses yet another additive for fuels andlubricants which, in this case, is prepared by reacting aromaticcompounds, such as phenol or substituted phenol including alkyl groupsof at least 50 carbon atoms, with an aldehyde, such as formaldehyde, anda non-amino hydrogen, active hydrogen compound, such as phenol,optionally along with an aliphatic alkylating agent of at least 30carbon atoms. This patent also discloses that sulfurized additivecompositions thereof can also be used as lubricant additives and fueloil additives. It does not disclose the use of alpha-olefins of lessthan 50 carbon atoms for the alkylation of phenol.

Another additive for improving the various cold flow characteristics ofhydrocarbon fuel compositions is disclosed in U.S. Pat. No. 4,564,460.In this patent the additives are broadly disclosed as including eitheran oil soluble ethylene backbone polymer or varioushydrocarbyl-substituted phenols as a first component and variousreaction products of hydrocarbyl-substituted carboxylic acylating agentsand amines and/or alcohols. The hydrocarbyl-substituted phenolconstituents of this overall additive are also broadly described, andthey can include repeating aromatic moieties, such as those shown incolumn 14 thereof, in which the R* groups include hydrocarbyl groups offrom 8 to 30 carbon atoms. These, in turn, can be provided by internalolefins or alphaolefins, and can be either straight or branched.Notwithstanding the extremely broad disclosure of this patent, not asingle working example is provided therein which makes or tests anyhydrocarbyl substituted phenol or aldehyde condensation product thereof.

British Patent No. 2,062,672 discloses another such additive, in thiscase including a sulfurized alkyl phenol and a carboxylic dispersant.The alkyl phenols disclosed in this patent can include alkyl radicals ofup to 1000 carbon atoms, but the disclosure also mentions the use ofmethylene-bridged alkyl phenols prepared by the reaction of the alkylphenol and formaldehyde.

Finally, Canadian Patent No. 1,192,539 discloses yet anotheralkyl-phenol-containing lubricant additive. In this case the lubricantis designed for two-cycle engines and the phenolic compound includes ahydrocarbyl group of an average of at least ten aliphatic carbon atoms.Furthermore, the disclosure states that the aromatic ring can be alinked polynuclear aromatic moiety, which can also include othersubstituents. Once again in this case the disclosure is very broad, andincludes innumerable variations on the alkyl phenol component.

Irrespective of all of the above, and the large number of additivecompositions which have previously been proposed and utilized foraltering the various flow properties of hydrocarbon oils and lubricatingoil compositions, the search has continued for additional flow improvingcompositions which cannot only significantly improve the flowcharacteristics of these various hydrocarbon compositions, but whichalso can be easily produced on an economical basis.

Commonly assigned U.S. patent applications Ser. Nos. 107,457 and107,507, both filed on Oct. 8, 1987 now U.S. Pat. Nos. 4,976,882 and5,039,437 respectively are directed to alkyl phenol aldehyde and sulfurbridged alkyl phenol condensates respectively and are incorporatedherein by reference.

SUMMARY OF THE INVENTION

In one aspect of the present invention, there is provided a novel methodof preparing alkylated phenols which minimizes rearrangement andprovides an essentially linear alkylated phenol. The alkyl phenols ofthe invention are prepared by conducting the alkylation in the presenceof polar-aprotic cosolvent. The alkyl phenols prepared as disclosed areespecially suited to preparing alkyl phenol formaldehyde condensates andsulfur bridged alkyl phenol formaldehyde.

In another aspect of the present invention, there is provided a polymercomposition having increased capability of improving the low temperatureflow properties of hydrocarbon oils comprising the condensation reactionproduct of reactants comprising alkylated phenol prepared by the methodof the instant invention, comprising at least 80 mole % difunctionalalkylated phenol, and aldehyde wherein:

(a) the polymer composition has a number average molecular weight of atleast about 3,000 and a molecular weight distribution of at least about1.5;

(b) in the alkylated phenol reactant the alkyl groups (i) areessentially linear; (ii) have between 6 and 50 carbon atoms; and (iii)have an average number of carbon atoms between about 12 and 26; and

(c) not more than about 10 mole % of the alkyl groups on the alkylatedphenol have less than 12 carbon atoms and not more than about 10 mole %of the alkyl groups on the alkylated phenol have more than 26 carbonatoms.

In a preferred embodiment, the polymeric composition can be representedby the formula: ##STR1## wherein (a) R' comprises C₁ to C₃₀ alkyl; (b)R₁ represents alkyl derived from linear alpha-olefins having from 6 to50 carbon atoms; (c) R₂, R₃, R₄ and R₅ represent hydrogen or alkylderived from linear alpha-olefins having from 6 to 50 carbon atoms,provided that at least one of R₂ and R₃ and at least one of R₄ and R₅are alkyl; (d) in the alkyl groups constituting R₁ to R₅ ; (i) theaverage number of carbon atoms is between about 12 and 26; (ii) not morethan about 10 mole % of said alkyl groups have less than 12 carbon atomsand not more than about 10 mole % of said alkyl groups have more than 26carbon atoms; and (iii) the alkyl groups are essentially linear; (e) nis a number of at least about 5; and (f) the polymer has a numberaverage molecular weight of at least about 4,500 and a molecular weightdistribution of at least about 1.5. In a preferred embodiment, R' informula (I) comprises CH₂.

In another aspect of the present invention the polymeric compositionsare sulfurized, and preferably have a number average molecular weight ofat least about 5,000.

In another aspect of the the present invention, growing linear backbonesare crosslinked during formation with comonomer, which preferably can beeither a trifunctional comonomer having the formula: ##STR2## wherein R₆and R₇ can be hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl mercapto, orhalogen; or a tetrafunctional comonomer having the formula: ##STR3##wherein R₈ can be hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylmercapto, or halogen. In a preferred embodiment, R₆ and R₇ in formula(II) and R₈ in formula (III) are hydrogen.

In accordance with another aspect of the present invention, polymericadditives are provided by reacting alkylated phenol prepared by theprocess disclosed herein represented by the formula: ##STR4## wherein Rrepresents essentially linear alkyl having from 6 to 50 carbon atoms inwhich the average number of such carbon atoms in all of the alkyl groupsis between about 16 and 22, wherein not more than about 10 mole % of thealkyl groups have less than 16 carbon atoms and not more than about 10mole % of the alkyl groups have more than 22 carbon atoms, withformaldehyde, and optionally comonomer selected from formulas (II) and(III) above.

In accordance with the present invention, the condensation step isconducted in the presence of the trifunctional or tetrafunctionalcomonomer components discussed above.

DETAILED DESCRIPTION OF THE INVENTION

The additives of the present invention comprise fuel oil and lubricatingoil flow improvers which are effective for modification of the size,number, and growth of wax crystals in various hydrocarbon oils,including fuel oils and lubricating oils, so as to impart improved lowtemperature flow properties to these oils. Most particularly, when usedin connection with lubricating oil compositions, these lubricating oilflow improvers are also effective to improve the low temperaturehandling, pumpability, and/or vehicle operability as measured by suchtests as pour point and mini-rotary viscometry (MRV). When used inconnection with fuels, such as middle distillate petroleum fuels, suchas diesel fuels, heating oils and the like, these fuel oil flowimprovers are also effective to improve the low temperature handlingcharacteristics thereof, as most particularly measured by such tests ascloud point and pour point tests. Secondarily, these materials alsopossess anti-oxidant activity.

The additive compositions described above in the present invention areprepared by the alkylation of phenol conducted in the presence of atleast one polar aprotic cosolvent to minimize the amount ofrearrangement and to impart essential linearity to the alkyl group ofthe alkylate, followed by condensation with an aldehyde such asformaldehyde so as to produce polymers having certain specifiedmolecular weights. More particularly, the use of the specific linearalpha olefins which are set forth below in the manner described resultsin superior lubricating oil and fuel oil flow improvers relative toother alkyl phenolformaldehyde condensates employed in the prior art. Aswill be demonstrated, these particular polymers are particularly andunexpectedly superior in terms of their ability to co-crystallize withthe wax crystals in these hydrocarbon oils. Furthermore, in accordancewith other embodiments of the present invention condensate polymers areproduced in a sulfurized and/or more highly branched form, for molecularweight enhancement, and to thus further improve the low temperature flowproperties of these various hydrocarbon oils.

The particular alkyl phenol-aldehyde condensates which form the basicpolymeric additives are generally produced by the initial alkylationstep of the invention, followed by condensation with the aldehydecomponent.

Alkylation of the phenol is initially conducted with a linearalpha-olefin or blend of linear alphaolefins which are terminal olefins,as contrasted to internal olefins. In this manner, it is possible toproduce final polymers in which the alkyl group attached to the benzenering is essentially linear. By "essentially linear" is meant greaterthan 35, preferably at least 40, and most preferably at least 50 mole %of the alkyl groups derived from the olefin alkylating agent andattached to the aromatic ring of the phenol group (exclusive of thealkyl groups of any tri- or tetrafunctional optional comonomersdescribed hereinafter for molecular weight enhancement) in the alkylatedproduct is linear, except for a methyl group pendant from the carbonattached to that aromatic ring. More specifically, since terminalalpha-olefins are employed for the alkylation of phenol in accordanceherewith, the terminal olefins will attach to the aromatic ring at thebeta carbon thereof, thereby leaving the alpha carbon as a methyl grouppendant from the beta carbon of the original olefin. Thus, expresseddifferently, "essentially linear" means greater than 50 mole % of thealkyl groups of the alkylated phenol are alpha methyl substituted linearalkyl. The primary alkyl phenol product desired from this alkylationstep (after rearrangement as discussed hereinafter) will be linear to atleast that extent.

More specifically, the initial alkylation step itself is an exothermicreaction of phenol with these particular linear terminal alpha-olefins.This reaction can thus be shown as follows: ##STR5## and in whichreaction R is linear alkyl, and R' and R" are linear alkyl groupsderived in whole or in part from R. This exothermic reaction is thus asimple cationic reaction resulting in a somewhat complex product. In theideal reaction the olefin forms a carbonium ion species as a result ofthe presence of acidic conditions and temperatures. This cation can thenreadily react with phenol at either the ortho or para positions. Withoutrearrangement, the carbonium ion species will attach to the aromaticring at the beta carbon of the olefin, and R, will thus constitute apendant methyl group derived from the alpha carbon of the originalolefin, with R" constituting the remainder of the linear alkyl chainoriginally defined by R. In reality, however, many side reactions arepossible. Thus, the cation can revert back to the olefin or rearrangefurther down the linear chain, thereby producing attachment to thearomatic ring at a more internal carbon atom, and causing the length ofR' to increase, and R" to decrease in length correspondingly. It hasbeen found that if these rearrangements are too extensive, they willlead to the production of inferior products which would not suitablyinteract with the wax crystals of the lubricating oil or fuel oil towhich they are eventually added.

It is therefore critical to the present invention to minimize theserearrangements and to maximize the attachment of the alkyl groups at the2-position (i.e., beta carbon of the original linear olefin). Theinstant invention presents a novel method of producing alkyl phenolshaving essentially linear alkyl substituted groups. The presentinvention describes a method to produce alkyl phenols with lessrearrangement, and thereby an alkyl phenol-formaldehyde condensate withgreater pour point depressancy. The method involves conducting thealkylation of phenol in the presence of a polar aprotic cosolvent. Thecosolvents of the invention should have dielectric constants of greaterthan about 10 and desirably greater than about 20 or preferably adielectric constant in the range of from 20 to about 50. Typicalexamples of suitable cosolvents are 1,2-dichloroethane (e=10.4)hexamethylphosphoramide (e=21), N-methyl-2-pyrrolidone (e=32),nitrobenzene (e=35), nitromethane (e=36), N-N-dimethylformamide (e=37),acetonitrile (e=36), sulfolane (e=44) and dimethyl sulfoxide (e=47). Theuse of these polar aprotic cosolvents in the alkylation reactionsignificantly minimizes the amount of rearrangement by maximizing theattachment of the alkyl groups at the 2-position and thereby increasesthe pour point depressancy o the resulting alkyl phenol-formaldehydecondensates. The amount of solvent used is not critical and it would bewithin the knowledge of one skilled in the art to determine suitableamount without undue experimentation. Generally, amounts of above 50 wt.% of the reactant is considered suitable. Amounts, however, greatly inexcess of that stated above would not be considered detrimental, but maypresent problems with removal and would not be cost effective for theprocess. The minimum amount would be that necessary to produce thedesired product.

Other methods for minimizing such rearrangement are disclosed in U.S.application Nos. 107,457 and 107,507 now U.S. Pat. Nos. 4,976,882 and5,039,437 respectively. The methods disclosed in these patents arepreferably used in combination with the instant invention. The methodprimarily includes among others carrying out the alkylation process atlower reaction temperatures as opposed to elevated reactiontemperatures. Therefore, although the alkylation process itself cangenerally be conducted at temperatures of between about 50° and 200° C.,it was found that to employ alkylation temperatures of at or below about100° C., preferably at or below 90° C., e.g., typically between about50° and 100° C., and preferably between about 50° and 90° C., minimizedrearrangement.

It was also observed in the copending applications referenced above thatrearrangement is more likely to occur at the para position than theortho position. This is probably a result of a steric factor whichpermits greater accommodation of rearrangement at the para position tothe hydroxyl group.

Accordingly, the definition of "essentially linear" accounts for, andexpresses the permissible limits of, the above-discussed autogenousrearrangement in forming the alkylate product. In short, "essentiallylinear" expresses the maximum degree of acceptable branching in thealkylate product which can be tolerated when starting with linearalpha-olefins. The degree of rearrangement is typically determined by ¹H-NMR and/or by high pressure liquid chromatography.

Another critical aspect in the preparation was found to be the carbonnumber and carbon number distribution of olefins employed foralkylation.

The particular linear alpha-olefins used in connection with thealkylation step of the present invention was, as indicated above, foundto be crucial to the manufacture of the proper additives for use herein.These linear alpha-olefins have the formula CH₂ ═CH--R, in which R isstraight chain alkyl having between about 4 and about 48 carbon atoms,and in which the specific alpha-olefin or mixture of alpha-olefins usedfor this alkylation has an average carbon number (on a molar basis formixtures of olefins) of between about 12 and 26 (e.g. 14 and 24),preferably between about 16 and 22 (e.g., 17 and 21, or 16 and 19), andmost preferably between about 18 and 20.

Moreover, the olefin mixture as was disclosed should not contain morethan about 10 mole %, preferably not more than about 5 mole %, and mostpreferably not more than about 2 mole % of alpha-olefins havingindependently: (a) less than about 12, preferably not less than about14, and most preferably not less than about 16 carbon atoms; and (b) notmore than about 26, preferably not more than about 24, and mostpreferably not more than about 22 carbon atoms. These proportionalrequirements are incorporated into, and embodied in, the finalcondensate polymer.

The particular average carbon number range which was most desirabledepended upon the ultimate environment of the alkyl phenol condensatewhich was produced thereby.

More particularly, it has thus been found that in connection with suchfuel oils, including diesel fuels and heating oils, to maximize cloudpoint reduction an average carbon number of about C₁₈ is most desired,while to maximize pour point reduction an average carbon number of aboutC₁₆ was most desired.

On the other hand, in connection with lubricating oil compositions theaverage carbon number for maximizing pour point number reduction was anaverage carbon content of from about C₁₈ to C₂₀.

Moreover, within each class of hydrocarbon oils, i.e., fuel orlubricating oil, each specific hydrocarbon oil can be associated with anoptimum average carbon number for the R group (also referred to hereinas the alkylate average carbon number) to achieve maximum cloud point orpour point depressancy relative to the base oil without any additive.Optimum pour depressancy will typically be achieved by an average carbonnumber that is lower than that needed to achieve optimum cloud pointdepressancy for a given hydrocarbon oil.

It was further found that while the molecular weight and molecularweight distribution M_(w) /M_(n) of the condensate polymer, degree ofbranching, and concentration of the condensation polymer in thehydrocarbon oil all affect, and are important for achieving lowtemperature flow performance, the two most dominant factors are theoptimum alkylate average carbon number and the essential linearity ofthe alkyl group.

It was also believed that in any given situation the use of a range ofalpha-olefins surrounding the optimum average carbon number was superiorto the use of a single alpha-olefin having that number of carbon atoms.In any event, the most preferred alpha-olefins for use will include1-hexadecene, 1-octadecene, 1-eicosene, 1-docosene, 1-tetracosene, andmixtures thereof.

A further important factor in conducting the alkylation reaction was theminimization of monofunctional alkylation product (e.g., most dialkylateproducts) and the maximization, relative to monofunctional alkylate, ofdifunctional alkylate products (e.g., mono alkylates) in the phenolalkylation reaction. As discussed hereinafter, the final alkyl phenolaldehyde condensation product is synthesized to possess certain minimumrequirements in terms of molecular weight and molecular weightdistribution. If the alkylated phenol product mixture employed forcondensation contains too much monofunctional dialkylate, then the finalcondensation polymer will not meet such requirements. This stems fromthe fact that when a second alkyl group attaches to the phenol to yielda 2,4- or a 2,6-dialkyl phenol, it results in a monofunctionaldialkylate molecule which, if reacted with a growing polymer chain,would terminate chain growth in the following manner: ##STR6##

More specifically, the functionality of the alkylated-phenol reactionproduct expresses the number of available reactable sites, which remainon the alkylated phenol after alkylation, that can participate in thepolymerization reaction through propagation of a growing polymer chain.The only freely reactable sites on an unsubstituted phenol molecule forpurposes of polymerization are the 2-, 4-, and 6-carbons of the phenolaromatic ring. Thus, unsubstituted phenol is a trifunctional molecule.If monoalkylation occurs at only one of the 2-, 4-, or 6-positions, theresulting mono-alkylate is said to be difunctional, since one of thereactable sites has been eliminated through substitution of an alkylgroup thereon. Similarly, the substitution of alkyl groups at any two ofthe 2-, 4-, or 6-carbons of the phenol molecule through dialkylationwill result in the formation of a monofunctional dialkylate product.Thus, 2,4-dialkyl phenol and 2,6-dialkyl phenol are monofunctionaldialkylates which will lead to chain termination, and thereby limitpolymer molecular weights. While 2,5-dialkyl phenol and 3,5-dialkylphenol are difunctional and trifunctional dialkylate monomers,respectively, such monomers do not normally form under typicalalkylation conditions, because such formation would involve reaction atnormally unreactive sites. Consequently, one seeks to minimizedialkylation generally, as most dialkylation leads to the formation ofmonofunctional monomer. Thus, reference to dialkylation herein as beingundesirable is technically a reference only to dialkylation which yieldsmonofunctional dialkylate.

An equation relating the maximum degree of polymerization (DP) to theextent of reaction (p) and the functionality (f) of the reactants isreferred to as the Modified Carothers Equation:

    DP=2/2-Pf)

This equation can be used to show that a monofunctional dialkylatemonomer severely limits the maximum degree of polymerization in thealkyl phenolaldehyde condensation reaction.

As was disclosed in the Applications incorporated herein by reference,the use of separately synthesized triand tetrafunctional comonomers canbe employed to increase the molecular weight of the final condensationpolymer and/or to compensate for the presence of monofunctionaldialkylate monomer.

Thus, the target molecular weights as disclosed was suitably achieved bycontrolling the amount of difunctional (e.g., monoalkylate) monomer tobe typically at least about 80 mole %, and preferably at least about 85mole %, and most preferably at least about 90 mole %, and typically fromabout 80 to about 100 mole %, preferably from about 85 to 100 mole %,and most preferably from about 90 to 100 (e.g., 95 to 100) mole %, basedon the total moles of alkylate monomer in the monomer mixture intendedfor polymerization.

Correspondingly, the amount of monofunctional dialkylate monomer whichcan be tolerated will typically range from about 0 to about 20 mole %,preferably from about 0 to about 15 mole %, and most preferably fromabout 0 to about 10 (e.g. 0 to about 5) mole % based on the moles ofmonomer in the alkylate monomer mixture.

High functionality monomers, such as the tri- and tetrafunctionalcomonomers described hereinafter, are typically employed in collectiveamounts of from about 0 to about 10 mole %, preferably from about 2 toabout 8 mole %, and most preferably from about 3 to about 5 mole %,based on the total moles of alkylate monomer in the alkylate monomermixture.

One way to minimize dialkylation in attempting to meet the condensationpolymer molecular weight targets specified hereinafter was to employexcess phenol relative to the olefin for the alkylation reaction.Accordingly, effective molar ratios of phenol to olefin can varytypically from about 2:1 to about 10:1 (or higher), preferably fromabout 2:1 to about 5:1. From a process standpoint, however, too much ofan excess of phenol can be disadvantageous because of the need to removethe excess phenol from alkylation product after alkylation is completed.

Thus, it was found that certain zeolite catalysts permit one to lowerthe phenol:olefin molar ratio to less than about 2:1, preferably betweenabout 1.7:1 and 1:1 and still achieve minimization of dialkylation. Thislow ratio extremely simplifies unreacted phenol recovery.

The alkylation reaction can generally be accomplished, within the aboveparameters, by a number of techniques known to those skilled in thisart. One particularly suitable technique disclosed using theFriedel-Crafts reaction which occurs in the presence of a Lewis acidcatalyst, such as boron trifluoride and its complexes with ethers,hydrogen fluoride, etc., aluminum chloride, aluminum bromide, and zincdichloride, etc. Methods and conditions for carrying out such reactionsare well known to those skilled in this art, and reference is made, forexample, to the discussion in the article entitled "Alkylation ofPhenols", in Kirk Othmer Encyclopedia of Chemical Technology, 2ndEdition, Vol. 1, pp. 894-895, Interscience Publishers, Division of JohnWiley and Company, New York, 1963, which is incorporated herein byreference thereto. A particularly preferred catalyst for use in suchalkylation reactions is designated Amberlyst 15 by the Rohm and HaasCompany. This catalyst is included among the strongly acidicmacroreticular resins patented under U.S. Pat. No. 4,224,415. This resinis itself composed of long chains of polystyrene locked together bydivinylbenzene crosslinks into a threedimensional, insoluble polymericphase called a matrix, on which are attached sulfonic acid groups (--SO₃H). Amberlyst 15 possesses high acidity (4.7 meq/g), high porosity (32%)and high surface area (45 m² /g).

In a highly preferred method for carrying out the alkylation reaction asdisclosed herein, a zeolite catalyst is employed for use in theselective production of the desired mono-alkylate. More particularly,acidic crystalline zeolites are used which have high silica to aluminaratios and which have effective pore sizes of between about 6 and 8Angstroms, and include a number of commercial zeolite catalysts, such aLZ-Y82 catalyst manufactured by Union Carbide Corporation. In any event,a general description of these zeolites is set forth in Young, U.S. Pat.No. 4,283,573, which is incorporated herein by reference thereto. Ingeneral, these zeolites have a crystal structure which provides accessto and egress from the intracrystalline free space of the zeolites byvirtue of having channels or networks of pores, the openings of whichagain preferably have a major dimension, or a free pore diameter, ofbetween about 6A and about 8A. These zeolites are also characterized bypore apertures of about a size as would be provided by 12-member ringsof silicon and aluminum atoms. The preferred types of zeolites for usein this invention possess a silica to alumina molar ratio of from about3:1 to about 6:1. This ratio represents, as closely as possible, theratio in the rigid anionic framework of the zeolite crystal.Furthermore, these preferred zeolites will have a high surface area,such as about 625 m² /g. The use of these zeolite catalysts thus permitsone to eliminate the expensive and difficult distillation step requiredto separate the mono-alkylate from the di-alkylate produced with theacid-type catalysts previously utilized.

In connection with the alkylated phenol product, the use of a linearalpha-olefin or a mixture of linear alpha-olefins gives a ratio of orthoto para attachments on the phenol of about 2:1. In contrast with thealkylated phenol product of this reaction, the use of a branchedinternal olefin or a mixture of branched internal olefins gives a ratioof ortho to para attachments on phenol of about 1:18. However,essentially linear alkyl groups attached either ortho or para to thehydroxy group perform equally well.

The next step in the preparation of the polymer additives utilizing theessentially linear alkylated phenol prepared as taught herein is theactual polymerization or condensation reaction. The reaction itself is acondensation of the above-described alkyl phenol in the presence ofaldehyde or the functional equivalent thereof. The function of thealdehyde is to bridge and link the alkyl phenol monomer. In particular,aliphatic ketones and aldehydes can be used herein to perform thebridging function and include those represented by the formulaR--C(O)R', where R and R' are hydrogen or an alkyl group having at least1 carbon atom, and generally between between 1 and 30 carbon atoms. Mostpreferably R, will be hydrogen, i.e., in the case of the aldehydes, andfrom a practical standpoint, these aldehydes (or the correspondingketones) will generally range from 1 to about 20 carbon atoms, andpreferably from 1 to about 10 (e.g., 1 to 7) carbon atoms, withformaldehyde being highly preferred. Other aldehydes which can be usedherein but which are less preferred than formaldehyde are acetaldehyde,2-ethylhexanal, and propionaldehyde. In addition, aromatic aldehydes,such as benzaldehyde, may also be utilized. The term formaldehyde asused in connection with this invention includes reactive equivalents offormaldehyde under reaction conditions, a reversible polymer thereofsuch as paraformaldehyde, trioxane, or the like, and can thus beproduced from the decomposition of paraformaldehyde, etc.

The condensation reaction with the alkylated phenol composition isgenerally carried out at temperatures in the range of from about 50° C.to about 150° C., preferably in the range of from about 75° C. to about125° C. Temperatures below about 50° C. are undesirable as the rate ofreaction is unduly slow, while temperatures above about 250° C. can beused, but will normally result in degradation of the materials. Thereaction is generally carried out in the presence of an acidic or basicmaterial. The preferred acid catalysts which may be employed includehydrochloric acid, phosphoric acid, acetic acid, oxalic acid, and strongorganic acids, such as p-toluenesulfonic acid, etc. While the relativeproportions of the ingredients used are not critical, it is generallydesirable to use a mole ratio of alkyl phenol to aldehyde in the rangeof from about 2:1 to about 1:4, and preferably of about 1:1. While theamount of acid or basic catalyst used in the formaldehyde-alkyl phenolcondensation reaction is also not critical, it is usually convenient touse about 1 to 5 wt. %, based on the amount of formaldehyde used in thereaction.

The reaction between the alkylated phenol and the formaldehyde may becarried out in the absence of a diluent, but it is often convenient touse a suitable diluent, typically a substantially inert organic diluentsuch as mineral oil or an alcohol, ether, ether alcohol or the like,such as diluents including benzene, toluene, xylenes, paraffins, and thelike. Diluents may be advantageous in aiding the maintenance of reactiontemperatures and in the removal of water of reaction therefrom.

Furthermore, pressure is also not a critical factor, and can beatmospherical or below up to 1000 psi or higher. Atmospheric pressure ispreferred for convenience, and the pressure should be sufficient tomaintain the reactants in the liquid phase.

The reactants, together with the catalyst and any diluent which isemployed, can thus be charged to a reactor and reacted under theconditions set forth above. Water of reaction, together with any waterthat may have been introduced with the initial charge, is removed duringthe course of the reaction to drive the condensation to completion. Thiscan most conveniently be done by overhead distillation, although othertechniques known in the art can also be employed. The condensation isessentially complete when no further water of reaction is eliminated.The crude reaction product mixture can then be cooled, neutralized,waterwashed to remove the catalyst, dried, and then stripped to removeexcess reactant, any unreacted materials, and any diluent that may havebeen used.

The condensation reaction is conducted in a manner and under conditionssufficient to achieve or surpass certain minimum number average andweight average molecular weight targets. Accordingly, the condensationreaction is conducted to impart to the final polymer a number averagemolecular weight (M_(n)) as determined by vapor-phase osmometry of atleast about 3,000 (e.g., at least about 4,000), preferably at leastabout 5,000, and most preferably at least about 7,000, and typicallyfrom about 3,000 to about 60,000 (e.g., 4,000 to 60,000), preferablyfrom about 5,000 to about 30,000, most preferably from about 7,000 toabout 20,000, and a weight average molecular weight (M_(w)) asdetermined by gel permeation chromatography, of at least about 4,500(e.g., at least about 5,000), preferably at least about 6,000, andtypically from about 4,500 to about 100,000, preferably from about10,000 to about 70,000 (e.g., 6,000 to about 35,000), and mostpreferably from about 20,000 to about 50,000.

The maximum number and weight average molecular weights are limited onlyby the solubility of the condensate polymer in the particularhydrocarbon basestock in question.

It is most preferred that these polymers have a ratio of weight averagemolecular weight to number average molecular weight (M_(w) /M_(n)),commonly referred to as molecular weight distribution, of greater thanabout 1.5, preferably greater than about 2.0, and most preferablygreater than about 2.5, and typically from about 1.5 to about 34,preferably from about 2.0 to about 24, and most preferably from about3.0 to about 7.0. Generally, the higher the weight average molecularweight, the better suited or more effective these polymers are forimproving the flow properties of various hydrocarbon oils in accordancewith the present invention.

While number average molecular weight (M_(n)) can conveniently also bedetermined by gel permeation chromatography (GPC), it is considered thatVPO techniques are more accurate, although the M_(n) by the GPCtechnique will typically approximate M_(n) by VPO within ±1000, moretypically ±500.

In one embodiment, polymers or condensates which are thus produced inaccordance with this process can be represented by the followingformula: ##STR7## in which R' is an alkyl group derived from the ketoneor aldehyde reactant having from 1 to 30 carbon atoms, and preferablyhaving from 1 to 20 carbon atoms, R₁ represents attached essentiallylinear alkyl groups discussed above derived from the linear alpha-olefinhaving from about 6 to 50 carbon atoms, in which the average number ofcarbon atoms in all of the groups constituting R₁ is between about 12and 26, preferably between about 16 and 22, and most preferably betweenabout 18 and 20, and in which no more than about 10 mole % of alkylgroups have less than 12 carbon atoms and no more than about 10 mole %of alkyl groups have more than 26 carbon atoms; R₂, R₃, R₄ and R₅independently can represent hydrogen or alkyl as described in connectionwith R₁, with the proviso that at least one of R₂ and R₃ is said alkyland at least one of R₄ and R₅ is said alkyl. The hydroxy group of thephenol will be located on an aromatic carbon which is adjacent to acarbon on which at least one of the R, groups is attached.

The value of n is subject to the number average molecular weight targetsdiscussed above, and the minimum value thereof expressed hereinafterwill consequently vary depending on the average carbon number of theolefins employed for alkylation and the number of repeating unitscontrolled by n necessary to achieve such M_(n) values when accountingfor said olefin average carbon number.

Accordingly, n is a number which, subject to the above constraints, willtypically be at least 5 (e.g., at least 8), preferably at least 10(e.g., at least 12), and most preferably at least 15, and can varytypically from about 5 to about 80, preferably from about 10 to about60, and most preferably from about 15 to about 30.

As indicated above, it can be somewhat difficult to increase themolecular weights of the alkylated phenolaldehyde condensates beyond acertain level because of the propensity of dialkylate monomers toterminate chain growth

One such way to further increase molecular weight is to form asulfurized alkylated phenol-aldehyde condensate polymer. Suchsulfurization can be carried out by employing a sulfurizing agent, suchas elemental sulfur or a sulfur halide such as sulfur monochloride, orpreferably sulfur dichloride. The sulfurization reaction itself istypically effected by heating the alkylated phenol-aldehyde reactionproduct with the sulfurizing agent at temperatures of between about 50°and 250° C., and preferably of at least about 160° C. if elementalsulfur is used, and optionally in the presence of a suitable diluentsuch as those recited above. This is carried out for a period of timesufficient to effect substantial reaction with the sulfurizing agent. Itis generally preferable to incorporate between about 5 and 10 wt. % ofsulfur into the alkylated phenol-aldehyde product. Particularly in thosecases where a sulfur halide is used as the sulfurizing agent, it isfrequently preferred to use an acid acceptor such as sodium hydroxide,sodium acetate or the like to react with the hydrogen halide evolvedtherein. The precise molecular structure of the product formed bysulfurization is believed to be a sulfur and alkylene (e.g., methylene)bridged polyphenol composition. By doing so, the number averagemolecular weight of these compositions can be increased to greater thanabout 6,000, and the weight average molecular weight, as determined bygel permeation chromatography, to greater than about 8,000, andpreferably between about 10,000 and 100,000 (once again as limited bythe solubility of these compositions in the particular basestocksinvolved). Furthermore, incorporation of sulfur provides anti-oxidantproperties for these additives. A less preferred alternative method forachieving sulfurization is to incorporate the sulfurizing agent into thecondensation reaction mixture.

There are yet additional and/or alternative methods of increasing themolecular weight of the alkylated phenol-aldehyde condensate flowimprovers of the present invention. In one such method, thepolymerization step is carried out in the additional presence oftrifunctional or tetrafunctional comonomer (functionality beingreactable sites) so as to produce an ultimate condensation polymerhaving a branched backbone rather than linear backbone as shown informula (I) hereabove, wherein said linear backbones are crosslinkedthrough these tri- and tetrafunctional monomers.

In particular, a trifunctional comonomer having the following formulacan be employed: ##STR8## in which R₆ and R₇ can be hydrogen, alkyl,aryl, alkoxy, aryloxy, alkyl mercapto, and halogen. More particularly,it is preferred that R₆ and R₇ include branched or straight chain alkylgroups, preferably straight chain, such as C₁ through C₃₀ alkyl,preferably methyl, C₆ through C₁₄ aryl, C₁ through C₂₂ alkoxy, C₆through C₁₄ aryloxy, C₁ through C₃₀ alkyl mercapto, and preferablyhalogens such as chlorine and bromine.

As discussed above, 3,5-dialkylate is difficult to achieve under normalalkylation conditions. Consequently, a variety of methods well known inthe art can be employed to achieve 3,5-dialkylation. One such methodinvolves a thallation reaction wherein, for example, 1,3-dimethylbenzene is contacted with a thallium trifluoro acetate catalyst to causestereo specific oxidation to 3,5-dimethyl phenol.

Representative examples of trifunctional monomers include phenol,m-cresol, 3,5-xylenol, m-phenyl phenol, m-methoxyphenol, orcinol, andm-methyl mercapto phenol, while phenol is preferred.

For example, when phenol is employed as the trifunctional monomer, thena portion of the branched backbone can be represented by the followingformula with an asterisk indicating the original phenol trifunctionalmonomer: ##STR9##

It is thus possible in this manner to produce such polymer condensateshaving weight average molecular weights determined by gel permeationchromatography of greater than about 10,000, preferably between about10,000 and 100,000, and most preferably greater than about 20,000.

Even further branching is achieved with tetrafunctional monomer, whichcan crosslink four linear backbones.

The tetrafunctional comonomers which can be used in the polymerizationstep of the present invention can have the formula: ##STR10## in whichR₈ independently can be the same hydrogen, alkyl, aryl, alkoxy, aryloxy,alkyl mercapto, and halogen components discussed above in connectionwith the trifunctional comonomers as formula II hereof. Representativeexamples of suitable tetrafunctional comonomers include bisphenol A,bisphenol B, methylene-4,4,-bis (3,5-dibutyl phenol), methylene-4,4,-bis(3,5-dimethoxy phenol), and methylene-4,4,-bis (3,5-dimethyl mercaptophenol), with bisphenol A being preferred. Again, in this case it isalso possible to produce such polymer condensates having weight averagemolecular weights determined by gel permeation chromatography of greaterthan about 10,000, preferably between about 10,000 and 100,000, and mostpreferably greater than about 20,000.

The amount of such trifunctional and/or tetrafunctional comonomeremployed in the polymerization or condensation step of the presentinvention must, however, be limited to a certain extent. That is, theamount of comonomer present should be less than about 10 wt. % of acombination of the alkylated phenol and the aldehyde, and preferablyless than about 8 wt. %. It has thus been found that if too great anamount of the trifunctional and/or tetrafunctional comonomer is present,that material tends to crosslink to the extent that an insoluble masscan be formed thereby. This can be avoided, however, by using theamounts discussed above, and additionally by conducting thepolymerization in the presence of small amounts of the trifunctional ortetrafunctional comonomer. Also, this comonomer can be continuouslyadded during the course of polymerization, thereby becoming diluted withthe polymerizing alkyl phenol composition to maintain the comonomer asdilute as possible throughout the polymerization reaction.

It is also contemplated, although less preferred, that blends ofseparately synthesized alkyl phenol condensates meeting theaforedesoribed requirements can be employed.

For purpose of discussion, when such blends are employed, the overallalkylate average carbon number for each polymer component in the blendin which the alkylate portion thereof is derived from a singlealpha-olefin, or single mixture of alpha-olefins, can also be referredto herein as the alkylate intra-molecular carbon average. However, thealkylate intra-molecular carbon average of each polymer component in theblend can then also be averaged on a molar basis to determine what isreferred to herein as the alkylate inter-molecular carbon average forthe blend.

It has been found that when the optimum alkylate average carbon number(i.e., intra-molecular average carbon number) has been determined for aparticular hydrocarbon oil, the best low temperature performance isachieved by a single polymer which possesses this optimum average carbonnumber value, rather than a blend of polymers wherein each polymercomponent in the blend possesses a non-optimum alkylate intra-molecularcarbon average, but the blend collectively possesses an alkylateinter-molecular carbon average value equal to the value of the optimumintramolecular carbon average.

The polymer additives produced in accordance with the present inventionhave been found to be useful in fuel oils and lubricating oils. Thenormally liquid fuel oils are generally derived from petroleum sources,e.g., normally liquid petroleum distillate fuels, though they mayinclude those produced synthetically by the Fischer-Tropsch and relatedprocesses, the processing of organic waste material or the processing ofcoal, lignite or shale rock. Such fuel compositions have varying boilingranges, viscosities, cloud and pour points, etc., according to their enduse as is well known to those of skill in the art. Among such fuels arethose commonly known as diesel fuels, distillate fuels, heating oils,residual fuels, bunker fuels, etc., which are collectively referred toherein as fuel oils. The properties of such fuels are well known toskilled artisans as illustrated, for example, by ASTM Specification D#396-73, available from the American Society for Testing Materials, 1916Race Street, Philadelphia, Pa. 19103.

Particularly preferred fuel oils include middle distillates boiling fromabout 120° to 725° F. (e.g., 375° to 725° F.), including kerosene,diesel fuels, home heating. fuel oil, jet fuels, etc., and mostpreferably whose 20% and 90% distillation points differ by less than212° F., and/or whose 90% to final boiling point range is between about20 and 50° F. and/or whose final boiling point is in the range of 600°to 700° F.

The additives produced using the process of this invention find theirprimary utility, however, in lubricating oil compositions, which employa base oil in which the additives are dissolved or dispersed. Such baseoils may be natural or a mixture of natural and synthetic oils.

Thus, base oils suitable for use in preparing the lubricating oilcompositions of the present invention include those conventionallyemployed as crankcase lubricating oils for spark-ignited and compressionignited internal combustion engines, such as automobile and truckengines, marine and railroad diesel engines, and the like. Advantageousresults are also achieved by employing the additives produced using theprocess of this invention in base oils conventionally employed in and/oradapted for use as power transmitting fluids such as automatictransmission fluids, tractor fluids, universal tractor fluids andhydraulic fluids, heavy duty hydraulic fluids, power steering fluids andthe like. Gear lubricants, industrial oils, pump oils and otherlubricating oil compositions can also benefit from the incorporationtherein of the additives produced as described herein.

Thus, the additives produced as disclosed herein may be suitablyincorporated into mixtures of natural and synthetic base oils providedthese mixtures include at least about 80 wt. % of natural base oil.Suitable synthetic base oils for use in these mixtures include alkylesters of dicarboxylic acids, polyglycols and alcohols;polyalphaolefins, polybutenes, alkyl benzenes, organic esters ofphosphoric acids, polysilicone oils, etc.

Natural base oils include mineral lubricating oils which may vary widelyas to their crude source, e.g., whether paraffinic, naphthenic, mixed,paraffinic-naphthenic, and the like; as well as to their formation,.e.g., distillation range, straight run or cracked, hydrofined, solventextracted and the like.

More specifically, the natural lubricating oil base stocks which can beused in the compositions of this invention may be straight minerallubricating oil or distillates derived from paraffinic, naphthenic,asphaltic, or mixed base crudes, or, if desired, various blends of oilsmay be employed as well as residuals, particularly those from whichasphaltic constituents have been removed. The oils may be refined byconventional methods using acid, alkali, and/or clay or other agentssuch as aluminum chloride, or they may be extracted oils produced, forexample, by solvent extraction with solvents of the type of phenol,sulfur dioxide, furfural, dichlorodiethyl ether, nitrobenzene,crotonaldehyde, etc.

The lubricating oil base stock conveniently has a viscosity of typicallyabout 2.5 to about 12, and preferably about 2.5 to about 9 cSt. at 100°C.

Thus, the additives of the present invention can be employed in ahydrocarbon oil (i.e., fuel oil or lubricating oil) composition whichcomprises hydrocarbon oil, typically in a major amount, and theadditive, typically in a minor amount, which is effective to impart orenhance one or more of the low temperature flow properties describedherein. Additional conventional additives selected to meet theparticular requirements of a selected type of hydrocarbon oilcomposition can be included as desired.

The additives prepared in accordance with this invention are oilsoluble, dissolvable in oil with the aid of a suitable solvent, or arestably dispersible materials. Oil soluble, dissolvable, or stablydispersible as that terminology is used herein does not necessarilyindicate that the materials are soluble, dissolvable, miscible, orcapable of being suspended in oil in all proportions. It does mean,however, that the additives, for instance, are soluble or stablydispersible in oil to an extent sufficient to exert their intendedeffect in the environment in which the oil is employed. Moreover, theadditional incorporation of other additives may also permitincorporation of higher levels of a particular polymer adduct hereof, ifdesired.

Accordingly, while any effective amount of these additives can beincorporated into the fully formulated hydrocarbon oil composition, itis contemplated that such effective amount be sufficient to provide saidhydrocarbon oil composition with an amount of the additive of typicallyfrom 0.005 to 10, e.g., 0.01 to 2, and preferably from 0.025 to 0.25 wt.%, based on the weight of said composition.

The additives prepared by the process of this invention can beincorporated into the hydrocarbon oil in any convenient way. Thus, theycan be added directly to the oil by dispersing, or dissolving the samein the oil at the desired level of concentration, typically with the aidof a suitable solvent such as toluene, cyclohexane, or tetrahydrofuran.Such blending can occur at room temperature or elevated temperatures. Inthis form the additive per se is thus being utilized as a 100% activeingredient form which can be added to the oil or fuel formulation by thepurchaser. Alternatively, these additives may be blended with a suitableoil-soluble solvent and/or base oil to form a concentrate, which maythen be blended with a hydrocarbon oil base stock to obtain the finalformulation. Concentrates will typically contain from about 1 to 50%, byweight of the additive, and preferably from about 10 to 30% by weight ofthe additive.

The hydrocarbon oil base stock for the additives of the presentinvention typically is adapted to perform a selected function by theincorporation of additives therein to form lubricating oil compositions(i.e., formulations).

Representative additives typically present in such formulations includeviscosity modifiers, corrosion inhibitors, oxidation inhibitors,friction modifiers, dispersants, anti-foaming agents, anti-wear agents,pour point depressants, detergents, rust inhibitors and the like.

Viscosity modifiers, or viscosity index (V.I.) improvers impart high andlow temperature operability to the lubricating oil and permit it toremain shear stable at elevated temperatures and also exhibit acceptableviscosity or fluidity at low temperatures. These viscosity indeximprovers are generally high molecular weight hydrocarbon polymersincluding polyesters. The V.I. improvers may also be derivatized toinclude other properties or functions, such as the addition ofdispersancy properties.

These oil soluble V.I. polymers will generally have number averagemolecular weights of from about 40,000 to 1,000,000, preferably fromabout 40,000 to about 300,000, as determined by gel permeationchromatography or membrane osmometry.

Examples of suitable hydrocarbon polymers include homopolymers andinterpolymers of two or more monomers of C₂ to C₃₀, e.g., C₂ to C₈olefins, including both alpha-olefins and internal olefins, which may bestraight or branched, aliphatic, aromatic, alkyl aromatic,cycloaliphatic, etc. Frequently they will be of ethylene with C₃ to C₃₀olefins, particularly preferred being the copolymers of ethylene andpropylene. Other polymers can be used such as polyisobutylenes,homopolymers and interpolymers of C₆ and higher alpha-olefins, atacticpolypropylene, hydrogenated polymers and copolymers and terpolymers ofstyrene, e.g., with isoprene and/or butadiene.

More specifically, other hydrocarbon polymers suitable as viscosityindex improvers include those which may be described as hydrogenated orpartially hydrogenated homopolymers, and random, tapered, star, or blockinterpolymers (including terpolymers, tetrapolymers, etc.) of conjugateddienes and/or monovinyl aromatic compounds with, optionally,alphaolefins or lower alkenes, e.g., C₃ to C₁₈ alpha-olefins or loweralkenes. The conjugated dienes include isoprene, butadiene,2,3-dimethylbutadiene, piperylene and/or mixtures thereof, such asisoprene and butadiene. The monovinyl aromatic compounds include any ofthe following, or mixtures thereof, vinyl di- or polyaromatic compounds,e.g., vinyl naphthalene°, but are preferably monovinyl monoaromaticcompounds, such as styrene or alkylated styrenes substituted at thealpha-carbon atoms of the styrene, such as alpha-methylstyrene, or atring carbons, such as o-, m-, p-methylstyrene, ethylstyrene,propylstyrene, isopropyl-styrene, butylstyrene, isobutylstyrene,tert-butylstyrene (e.g., p-tertbutylstyrene). Also included arevinylxylenes, methylethyl styrenes and ethylvinylstyrenes. Alpha-olefinsand lower alkenes optionally included in these random, tapered and blockcopolymers preferably include ethylene, propylene, butene,ethylene-propylene copolymers, isobutylene, and polymers and copolymersthereof. As is also known in the art, these random, tapered and blockcopolymers may include relatively small amounts, that is less than about5 moles, of other copolymerizable monomers such as vinyl pyridines,vinyl lactams, methacrylates, vinyl chloride, vinylidene chloride, vinylacetate, vinyl stearate, and the like.

Specific examples include random polymers of butadiene and/or isopreneand polymers of isoprene and/or butadiene and styrene. Typical blockcopolymers include polystyrene-polyisoprene, polystyrene-polybutadiene,polystyrene-polyethylene, polystyrene-ethylene propylene copolymer,polyvinyl cyclohexane-hydrogenated polyisoprene, and polyvinylcyclohexane-hydrogenated polybutadiene. Tapered polymers include thoseof the foregoing monomers prepared by methods known in the art.Star-shaped polymers typically comprise a nucleus and polymeric armslinked to said nucleus, the arms being comprised of homopolymer orinterpolymer of said conjugated diene and/or monovinyl aromaticmonomers. Typically, at least about 80% of the aliphatic unsaturationand about 20% of the aromatic unsaturation of the star-shaped polymer isreduced by hydrogenation.

Representative examples of patents which disclose such hydrogenatedpolymers or interpolymers include U.S. Pat. Nos. 3,312,621; 3,318,813;3,630,905; 3,668,125; 3,763,044; 3,795,615; 3,835,053; 3,838,049;3,965,019; 4,358,565; and 4,557,849, the disclosures of which are hereinincorporated by reference.

The polymer may be degraded in molecular weight, for example bymastication, extrusion, oxidation or thermal degradation, and it may beoxidized and contain oxygen. Also included are derivatized polymers suchas post-grafted interpolymers of ethylene-propylene with an activemonomer such as maleic anhydride which may be further reacted with analcohol, or amine, e.g., an alkylene polyamine or hydroxy amine, e.g.,see U.S. Pat. Nos. 4,089,794; 4,160,739; 4,137,185; or copolymers ofethylene and propylene reacted or grafted with nitrogen compounds suchas shown in U.S. Pat. Nos. 4,068,056; 4,068,058; 4,146,489; and4,149,984.

Suitable hydrocarbon polymers are ethylene interpolymers containing from15 to 90 wt. % ethylene, preferably 30 to 80 wt. % of ethylene and 10 to85 wt. %, preferably 20 to 70 wt. % of one or more C₃ to C₈,alpha-olefins. While not essential, such interpolymers preferably have adegree of crystallinity of less than 10 wt. %, as determined by X-rayand differential scanning calorimetry. Copolymers of ethylene andpropylene are most preferred. Other alpha-olefins suitable in place ofpropylene to form the copolymer, or to be used in combination withethylene and propylene, to form a terpolymer, tetrapolymer, etc.,include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc.; alsobranched chain alpha-olefins, such as 4-methyl-1-pentene,4-methyl-1-hexene, 5-methyl-1-pentene, 4,4-dimethyl-1-pentene, and6-methyl-1-heptene, etc., and mixtures, thereof.

Terpolymers, tetrapolymers, etc., of ethylene, said C₃₋₈ alpha-olefin,and a non-conjugated diolefin or mixtures of such diolefins may also beused. The amount of the non-conjugated diolefin generally ranges fromabout 0.5 to 20 mole %, preferably from about 1 to about 7 mole %, basedon the total amount of ethylene and alpha-olefin present.

Corrosion inhibitors, also known as anticorrosive agents, reduce thedegradation of the metallic parts contacted by the lubricating oilcomposition. Illustrative of corrosion inhibitors are phosphosulfurizedhydrocarbons and the products obtained by reaction of aphosphosulfurized hydrocarbon with an alkaline earth metal oxide orhydroxide, preferably in the presence of an alkylated phenol or of analkylphenol thioester, and also preferably in the presence of carbondioxide. Phosphosulfurized hydrocarbons are prepared by reacting asuitable hydrocarbon such as a terpene, a heavy petroleum fraction of aC₂ to C₆ olefin polymer such as polyisobutylene, with from 5 to 30 wt. %of a sulfide of phosphorus for 1/2 to 15 hours, at a temperature in therange of about 66° to about 316° C. Neutralization of thephosphosulfurized hydrocarbon may be effected in the manner be effectedin the manner taught in U.S. Pat. No. 1,969,324.

Oxidation inhibitors, or antioxidants, reduce the tendency of mineraloils to deteriorate in service which deterioration can be evidenced bythe products of oxidation such as sludge and varnish-like deposits onthe metal surfaces, and by viscosity growth. Such oxidation inhibitorsinclude alkaline earth metal salts of alkylphenolthioesters havingpreferably C₅ to C₁₂ alkyl side chains, e.g., calcium nonylphenolsulfide, barium t-octylphenyl sulfide, dioctylphenylamine,phenylalphanaphthylamine, phosphosulfurized or sulfurized hydrocarbons,etc.

Other oxidation inhibitors or antioxidants. useful in this inventioncomprise oil-soluble copper compounds. The copper may be blended intothe oil as any suitable oil-soluble copper compound. By oil soluble itis meant that the compound is oil soluble under normal blendingconditions in the oil or additive package. The copper compound may be inthe cuprous or cupric form. The copper may be in the form of the copperdihydrocarbyl thio- or dithio-phosphates. Alternatively, the copper maybe added as the copper salt of a synthetic or natural carboxylic acid.Examples of same thus include C₁₀ to C₁₈ fatty acids, such as stearic orpalmitic acid, but unsaturated acids such as oleic or branchedcarboxylic acids such as napthenic acids of molecular weights of fromabout 200 to 500, or synthetic carboxylic acids, are preferred, becauseof the improved handling and solubility properties of the resultingcopper carboxylates. Also useful are oil-soluble copper dithiocarbamatesof the general formula (RR'NCSS)nCu (where n is 1 or 2 and R and R' arethe same or different hydrocarbyl radicals containing from 1 to 18, andpreferably 2 to 12, carbon atoms, and including radicals such as alkyl,alkenyl, aryl, arylalkyl, alkaryl and cycloaliphatic radicals.Particularly preferred as R and R¹ groups are alkyl groups of from 2 to8 carbon atoms. Thus, the radicals may, for example, be ethyl, n-propyl,i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl,n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl,cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. In order toobtain oil solubility, the total number of carbon atoms (i.e., R and R¹)will generally be about 5 or greater. Copper sulphonates, phenates, andacetylacetonates may also be used.

Exemplary of useful copper compounds are copper CuI and/or CuII salts ofalkenyl succinic acids or anhydrides. The salts themselves may be basic,neutral or acidic. They may be formed by reacting (a) polyalkylenesuccinimides (having polymer groups of M_(n) of 700 to 5,000) derivedfrom polyalkylene-polyamines, which have at least one free carboxylicacid group, with (b) a reactive metal compound. Suitable reactive metalcompounds include those such as cupric or cuprous hydroxides, oxides,acetates, borates, and carbonates or basic copper carbonate.

Examples of these metal salts are Cu salts of polyisobutenyl succinicanhydride, and Cu salts of polyisobutenyl succinic acid. Preferably, theselected metal employed is its divalent form, e.g., Cu+2. The preferredsubstrates are polyalkenyl succinic acids in which the alkenyl group hasa molecular weight greater than about 700. The alkenyl group desirablyhas a M_(n) from about 900 to 1,400, and up to 2,500, with a M_(n) ofabout 950 being most preferred. Especially preferred is polyisobutylenesuccinic anhydride or acid. These materials may desirably be dissolvedin a solvent, such as a mineral oil, and heated in the presence of awater solution (or slurry) of the metal bearing material. Heating maytake place between 70° and about 200° C. Temperatures of 110° C. to 140°C. are entirely adequate. It may be necessary, depending upon the saltproduced, not to allow the reaction to remain at a temperature aboveabout 140° C. for an extended period of time, e.g., longer than 5 hours,or decomposition of the salt may occur.

The copper antioxidants (e.g., Cu-polyisobutenyl succinic anhydride,Cu-oleate, or mixtures thereof) will be generally employed in an amountof from about 50 to 500 ppm by weight of the metal, in the finallubricating or fuel composition.

Friction modifiers serve to impart the proper friction characteristicsto lubricating oil compositions such as automatic transmission fluids.

Representative examples of suitable friction modifiers are found in U.S.Pat. No. 3,933,659 which discloses fatty acid esters, amides, andtertiary amines, e.g., hydroxy amines; U.S. Pat. No. 4,176,074 whichdescribes molybdenum complexes of polyisobutyenyl, succinicanhydride-amino alkanols; U.S. Pat. No. 4,105,571 which disclosesglycerol esters of dimerized fatty acids; U.S. Pat. No. 3,779,928 whichdiscloses alkane phosphonic acid salts; U.S. Pat. No. 3,778,375 whichdiscloses reaction products of a phosphonate with an oleamide; U.S. Pat.No. 3,852,205 which discloses S-carboxyalkylene hydrocarbyl succinimide,S-carboxyalkylene hydrocarbyl succinamic acid and mixtures thereof; U.S.Pat. No. 3,879,306 which discloses N-(hydroxyalkyl)alkenyl-succinamicacids or succinimides; U.S. Pat. No. 3,932,290 which discloses reactionproducts of di- (lower alkyl) phosphites and epoxides; and U.S. Pat. No.4,028,258 which discloses the alkylene oxide adduct of phosphosulfurizedN-(hydroxyalkyl) alkenyl succinimides; and succinate esters, or metalsalts thereof, of hydrocarbyl substituted succinic acids or anhydridesand thiobisalkanols such as described in U.S. Pat. No. 4,344,853. Thedisclosures of the above references are herein incorporated byreference.

Dispersants maintain oil insolubles, resulting from oxidation duringuse, in suspension in the fluid thus preventing sludge flocculation andprecipitation or deposition on metal parts. Suitable dispersants includehigh molecular weight alkyl succinimides, the reaction product ofoil-soluble polyisobutylene succinic anhydride with ethylene amines suchas tetraethylene pentamine and borated salts thereof.

Pour point depressants, otherwise known as lube oil flow improvers,lower the temperature at which the fluid will flow or can be poured.Such additives are well known. Typical of those additives which usefullyoptimize the low temperature fluidity of the fluid are C₈ -C₁₈dialkylfumarate-vinyl acetate copolymers, polymethacrylates, and waxnaphthalene.

Foam control can be provided by an antifoamant of the polysiloxane type,e.g., silicone oil and polydimethyl siloxane.

Anti-wear agents, as their name implies, reduce wear of metal parts.Representatives of conventional anti-wear agents are zincdialkyldithiophosphate and zinc diaryldithiosphate.

Detergents and metal rust inhibitors include the metal salts ofsulphonic acids, alkyl phenols, sulfurized alkyl phenols, alkylsalicylates, naphthenates and other oil-soluble mono- and di-carboxylicacids. Highly basic (viz, overbased) metal salts, such as highly basicalkaline earth metal sulfonates (especially Ca and Mg salts) arefrequently used as detergents. Representative examples of suchmaterials, and their methods of preparation, are found in co-pendingSer. No. 754,001, filed July 11, 1985, the disclosure of which is herebyincorporated by reference.

Some of these numerous additives can provide a multiplicity of effects,e.g., a dispersant-oxidation inhibitor. This approach is well known andneed not be further elaborated herein.

Compositions when containing these conventional additives are typicallyblended into the base oil in amounts which are effective to providetheir normal attendant function. Representative effective amounts ofsuch additives are illustrated as follows:

    ______________________________________                                                          Wt. % a.i.                                                                              Wt. % a.i.                                        Additive          (Broad)   (Preferred)                                       ______________________________________                                        Viscosity Modifier                                                                               .01-12   .01-4                                             Corrosion Inhibitor                                                                             0.01-5    .01-1.5                                           Oxidation Inhibitor                                                                             0.01-5    .01-1.5                                           Dispersant         0.1-20   0.1-8                                             Pour Point Depressant                                                                           0.005-10  .01-2                                             Anti-Foaming Agents                                                                             0.001-3   .001-0.15                                         Anti-Wear Agents  0.001-5   .001-1.5                                          Friction Modifiers                                                                              0.01-5    .01-1.5                                           Detergents/Rust Inhibitors                                                                       .01-10   .01-3                                             Mineral Oil Base  Balance   Balance                                           ______________________________________                                    

When other additives are employed, it may be desirable, although notnecessary, to prepare additive concentrates comprising concentratedsolutions or dispersions of the flow improver (in concentrate amountshereinabove described), together with one or more of said otheradditives (said concentrate when constituting an additive mixture beingreferred to herein as an additive package) whereby several additives canbe added simultaneously to the base oil to form the hydrocarbon oilcomposition. Dissolution of the additive concentrate into thehydrocarbon oil may be facilitated by solvents and by mixing accompaniedwith mild heating, but this is not essential. The concentrate oradditive-package will typically be formulated to contain the flowimprover additive and optional additional additives in proper amounts toprovide the desired concentration in the final formulation when theadditive-package is combined with a predetermined amount of basehydrocarbon oil. Thus, the products of the present invention can beadded to small amounts of base oil or other compatible solvents alongwith other desirable additives to form additive-packages containingactive ingredients in collective amounts of typically from about 2.5 toabout 90%, and preferably from about 5 to about 75%, and most preferablyfrom about 8 to about 50% by weight additives in the appropriateproportions with the remainder being base oil. For safetyconsiderations, the base oil for concentrates is typically a lubricatingoil rather than a fuel oil.

The final formulations may employ typically about 10 wt. % of theadditive-package with the remainder being base oil.

All of said weight percents expressed herein are based on activeingredient (a.i.) content of the additive, and/or upon the total weightof any additive package, or formulation which will be the sum of thea.i. weight of each additive plus the weight of total oil or diluent.

This invention will be further understood by reference to the followingexamples, wherein all parts are parts by weight and all molecularweights are either number average molecular weight determined byvapor-phase osmometry or weight average molecular weights determined bygel permeation chromatography as noted unless otherwise specified, andwhich include preferred embodiments of the invention.

The following examples are given as specific illustrations of theclaimed invention. It should be understood, however, that the inventionis not limited to the specific details set forth in the examples. Allparts and percentages in the examples, as well as in the remainder ofthe specification, are by weight unless otherwise specified.

EXAMPLE 1

This example is directed to the preparation of a typical alkylatedphenol component using the process disclosed in U.S. patent applicationSer. No. 107,507 and alkyl phenol-formaldehyde condensates producedthereby. Octadecyl phenol was prepared by charging into a four-neck,5-liter round bottom flask equipped with a mechanical stirrer, 933 gramsof phenol (9.93 moles) and 286 grams of Amberlyst 15 catalyst. A refluxcondenser, a thermometer, an addition funnel, and a nitrogen inlet tubewere attached to the flask and the mixture was heated to 70° C. Withstirring under a blanket of nitrogen, 834 grams (3.31 moles) of1-octadecene was added dropwise over a period of about one hour. Thetemperature was raised to 90° C. and maintained at this temperature forfour hours. The reaction mixture was then cooled to 50° C. and filteredto remove the catalyst. The excess phenol was removed by vacuumdistillation. The yield was 1,008 grams, or 88%. The product had arefractive index of 1.4859 at 25° C., a viscosity of 38.0 cP at 40° C.,and a hydroxyl number of 144 mg KOH/g. The infrared spectrum of theproduct showed absorption bands at 830 and 750 cm⁻¹, which arecharacteristic of alkyl phenols. The aromatic substitution pattern wasdetermined by ¹³ C-NMR spectroscopy and showed that the ortho to pararatio was 2.0:1.0. The alkyl substitution pattern was determined by ¹H-NMR spectroscopy and showed that the product consisted of 50 mole %2-substituted alkylate and 50 mole %≧3-substituted alkylate.

EXAMPLE 2

In order to demonstrate the criticality of the linearity of the alkylgroup used in the alkyl phenolformaldehyde condensates, Example 1 wasrepeated, except that in this case the mixture was heated to 115° C.instead of 90° C. The yield of octadecyl phenol was 893 grams, or 78%.The product had a hydroxyl number of 138 mg KOH/g, and its infraredspectrum showed absorptions at 830 and 750 cm⁻¹, which arecharacteristic of alkyl phenols. The aromatic substitution pattern wasdetermined by ¹³ C-NMR spectroscopy and showed that the ortho to pararatio was 1.8:1.0. The alkyl substitution pattern was determined by ¹H-NMR spectroscopy and showed that the product consisted of 35 mole %2-substituted alkylate and 65 mole %≧3-alkylate. The greater degree ofrearrangement in this alkyl phenol was due to the higher reactiontemperature.

EXAMPLE 3

In order to demonstrate the method of the present invention to producealkyl phenols with a less rearrangement, Example 1 was repeated, exceptthat a polar aprotic cosolvent, nitrobenzene, was added to the reactionmixture. Into a four-neck 1-liter round-bottom flask equipped with amechanical stirrer, 125 grams of phenol (1.33 moles), 31.5 grams ofAmberlyst 15 catalyst, and 164 grams of nitrobenzene were charged. Areflux condenser, a thermometer, an addition funnel and a nitrogen inlettube were attached to the flask and the mixture was heated to 70° C.With stirring under a blanket of nitrogen, 109 grams (0.43 moles) of1-octadecene was added dropwise over a period of about one hour. Thetemperature was raised to 90° C. and maintained at this temperature forfour hours. The reaction mixture was then cooled to 50° C. and filteredto remove the catalyst. The excess phenol and nitrobenzene were removedby vacuum distillation. The yield was 207 grams, or 99%. The infraredspectrum of the product showed absorption bands at 830 and 750 cm⁻¹,which are characteristic of alkyl phenols. The aromatic substitutionpattern was determined by ¹³ C-NMR spectroscopy and showed that theortho to para ratio was 1.7:1.0. The alkyl substitution pattern wasdetermined by ¹ H-NMR spectroscopy and showed that the product consistedof 59 mole % 2-substituted alkylate and 41 mole %≧3-substitutedalkylate, i.e., 18% less rearrangement than the alkylate produced inaccordance with Example 1.

EXAMPLE 4

Into a four-neck, 1-liter round-bottom flask, equipped with a mechanicalstirrer, a thermometer, an addition funnel, nitrogen inlet tube, and aDean-Stark trap with a reflux condenser, were charged 409 grams ofoctadecyl phenol produced in accordance with Example 1, 38 grams oftoluene, and 0.5 grams of p-toluenesulfonic acid monohydrate. Themixture was then stirred under a nitrogen blanket and heated to refluxconditions. During reflux, 32 grams of trioxane in 70 grams of toluenewere added dropwise over a period of about one hour. When the evolutionof water stopped, the reaction mixture was cooled and the toluene wasremoved in vacuo. The yield of octadecyl phenol-formaldehyde condensatewas 420 grams, or 99%. The number-average molecular weight of thedialyzed polymer was measured by vapor pressure osmometry as 4,110 andits weight-average molecular weight by gel permeation chromatography was12,000.

EXAMPLE 5

As another example of the preparation of an alkyl phenol-formaldehydecondensate polymer, Example 4 was repeated, except that the octadecylphenol produced in accordance with Example 2 was used. The yield ofoctadecyl phenol-formaldehyde condensate was 90%, and the number averageand weight-average molecular weight by gel permeation chromatography ofthe dialyzed polymer were 4,100 and 10,900, respectively.

EXAMPLE 6

As another example of the preparation of an alkyl phenol-formaldehydecondensate polymer, Example 4 was repeated, except that the octadecylphenol produced in accordance with Example 3 was used. The yield ofoctadecyl phenol-formaldehyde condensate was 96%, and the number-averageand weight-average molecular weights of the dialyzed polymer by gelpermeation chromatography were 4,700 and 9,500, respectively.

EXAMPLE 7

In order to demonstrate the criticality of the linearity of the alkylgroups used in the alkyl phenol-formaldehyde condensates, the octadecylphenol-formaldehyde condensates produced in accordance with Examples 4-6were tested for pour point depressancy in a lube basestock (ExxonS150N). Pour points were measured according to ASTM D 97 method, and theresults are set forth in Table 1 below. These results demonstrate that:(1) the 15-mole % reduction in alkylate containing a pendant methylgroup on the 2-carbon and a corresponding increase in alkylate havingsubstitution on the 3- or higher carbon decreases pour point depressancysignificantly (compare runs 1, 2 and 5); (2) the 9-mole % increase inalkylate containing a pendant methyl group on the 2-carbon and acorresponding decrease in the alkylate having substitution on the 3- orhigher carbon increases pour point depressancy significantly (compareruns 1, 2 and 8).

The decreased pour point depressancy of the octadecylphenol-formaldehyde condensate produced in accordance with Example 5,compared with Example 4, is because of the greater degree ofrearrangement in the alkylate used, i.e., Example 2. This results from ahigher reaction temperature.

The increased pour point depressancy of the octadecylphenol-formaldehyde condensate produced in accordance with Example 6,compared to Example 4, is because of lesser degree of rearrangement inthe alkylate used, i.e., Example 3. This results from the use of thepolar aprotic cosolvent, nitrobenzene.

                  TABLE 1                                                         ______________________________________                                        POUR POINT DEPRESSANCY OF OCTADECYL                                           PHENOL-FORMALDEHYDE CONDENSATES WITH                                          VARYING DEGREES OF ALKYLATE                                                   REARRANGEMENT                                                                                Additive                                                                      Conc.     2-Substituted                                        Run  Additive  (Wt. %)   Alkylate (%)                                                                           Pour Point (°F.)                     ______________________________________                                        1    Nil       0.00      --       +10, +15, +10                               2    Example 4 0.05      50       -10, -10, -10                               3    Example 4 0.10      50       -20, -25, -25                               4    Example 4 0.20      50        35, -35, -35                               5    Example 5 0.05      35       +10, +15, +15                               6    Example 5 0.10      35       -10, -10, -10                               7    Example 5 0.20      35       -25, -25, -30                               8    Example 6 0.05      59       -25, -25, -30                               9    Example 6 0.10      59       -35, -35, -40                               10   Example 6 0.20      59       -35, -40, -40                               ______________________________________                                    

What is claimed is:
 1. A method for producing a polymeric additivesuitable for improving the low temperature flow properties ofhydrocarbon oil which comprises (1) providing an alkylated phenol,comprising at lest 80 mol % difunctional alkylated phenol, derived fromreaction of (a) phenol and (b) linear alpha-olefin having (i) from 6 to50 carbon atoms, (ii) an average carbon number of from about 12 to 26;and (iii) not more than about 10 mole % containing less than 12 carbonatoms and not more than about 10 mole % containing more than 26 carbonatoms, said alkylation being conducted in the presence of an aproticpolar cosolvent in a manner and under conditions sufficient to renderand alkyl groups of said alkylated phenol essentially linear; and (2)condensing the alkylated phenol consisting essentially of alkylatedphenol provided in accordance with step (1) with a C₁ to C₃₀ aldehyde soas to produce a condensate of said alkylated phenol and said aldehydehaving a number average molecular weight of at least about 3,000 andmolecular weight distribution of at least about 1.5.
 2. The method ofclaim 1 including sulfurizing said condensate.
 3. The method of claim 1wherein said condensing step is conducted in the further presence of atleast one comonomer represented by the formula selected from the groupconsisting of: ##STR11## wherein R₆, R₇ and R₈ are each independentlyselected from the group consisting of hydrogen, alkyl, aryl, alkoxy,aryloxy, alkyl mercapto, and halogen, and wherein said comonomer ispresent in an amount of less than about 10 wt. % of said combination ofsaid alkylated phenol and said aldehyde.
 4. The method of claim 1wherein said linear alpha-olefin comprises a mixture of linearalpha-olefins.
 5. The method of claim 1 wherein said aldehyde comprisesformaldehyde.
 6. The method of claim 1 wherein the polar-aprotic solventhas a dielectric constant of greater than about
 10. 7. The method ofclaim 6 wherein the polar-aprotic solvent has a dielectric constant ofgreater than about
 20. 8. The method of claim 7 wherein the dielectricconstant of the polar-aprotic cosolvent ranges from about 20 to about50.
 9. The method of claim 1 wherein the polar-aprotic solvent isselected from the group consisting of nitrobenzene; nitromethane;N,N-dimethylformamide; acetonitrile, sulfolane, dimethyl sulfoxide. 10.The method of claim 9 wherein the polar-aprotic solvent is nitrobenzene.11. The method of claim 1 wherein the linear alpha-olefins compriseolefins having from C₆ to C₅₀ carbon atoms.
 12. The method of claim 11wherein the olefins have average carbon atom numbers between 12 and 26.13. The method of claim 12 wherein said alpha-olefins have averagecarbon atom numbers between 18 and
 20. 14. The method of claim 1 whereinthe alkylation is conducted at a temperature of from about 50° C. toabout 200° C.
 15. The method of claim 14 wherein the alkylation isconducted below 100° C.
 16. The method of claim 15 wherein thealkylation is conducted at a temperature of from 50° C. to 90° C. 17.The method of claim 1 wherein the molar ratio of phenol to olefin rangesfrom 2:1 to 10:1.
 18. The method of claim 17 wherein the molar ratio ofphenol to olefin is from about 2:1 to 5:1.
 19. The method of claims 1,4, 9, or 16 wherein said alkylation is conducted in the presence of anacidic crystalline aluminasilicate zeolite catalyst in order to minimizethe production of dialkylate therein.
 20. The method of claim 19 whereinsaid alkylation is conducted in the presence of a zeolite catalysthaving a silica to alumina ratio of about 3:1 to about 6:1.
 21. Themethod of claim 20 wherein said alkylation is conducted in the presenceof a zeolite catalyst having a surface area of at least about 625 m² /g.22. The method of claim 21 wherein said zeolite catalyst has a free porediameter of between about 6A and about 8A.
 23. The method of claim 1wherein said alkylation is conducted using a molar ratio of said phenolto said linear alpha-olefin of less than about 3:1.
 24. The method ofclaim 20 wherein said alkylation is conducted using a molar ratio ofsaid phenol to said linear alpha-olefin of between about 1.7:1 and about1:1.